Fix duplicate replies after message tool sends from named agents

pkg/agent/loop.go

@@ -458,7 +458,7 @@ func (al *AgentLoop) Run(ctx context.Context) error {
 				if target == nil {
 					cancelDrain()
 					if finalResponse != "" {
-						al.publishResponseIfNeeded(ctx, msg.Channel, msg.ChatID, finalResponse)
+						al.publishResponseIfNeeded(ctx, msg.SessionKey, msg.Channel, msg.ChatID, finalResponse)
 					}
 					return
 				}
@@ -518,7 +518,7 @@ func (al *AgentLoop) Run(ctx context.Context) error {
 				}
 
 				if finalResponse != "" {
-					al.publishResponseIfNeeded(ctx, target.Channel, target.ChatID, finalResponse)
+					al.publishResponseIfNeeded(ctx, target.SessionKey, target.Channel, target.ChatID, finalResponse)
 				}
 			}()
 		default:
@@ -604,15 +604,17 @@ func (al *AgentLoop) Stop() {
 	al.running.Store(false)
 }
 
-func (al *AgentLoop) publishResponseIfNeeded(ctx context.Context, channel, chatID, response string) {
+func (al *AgentLoop) publishResponseIfNeeded(
+	ctx context.Context,
+	sessionKey, channel, chatID, response string,
+) {
 	if response == "" {
 		return
 	}
 
 	alreadySent := false
-	defaultAgent := al.GetRegistry().GetDefaultAgent()
-	if defaultAgent != nil {
-		if tool, ok := defaultAgent.Tools.Get("message"); ok {
+	if agent := al.agentForSession(sessionKey); agent != nil {
+		if tool, ok := agent.Tools.Get("message"); ok {
 			if mt, ok := tool.(*tools.MessageTool); ok {
 				alreadySent = mt.HasSentInRound()
 			}

pkg/agent/loop_test.go

@@ -132,6 +132,76 @@ func TestProcessMessage_IncludesCurrentSenderInDynamicContext(t *testing.T) {
 	}
 }
 
+func TestPublishResponseIfNeeded_UsesSessionAgentMessageState(t *testing.T) {
+	tmpDir, err := os.MkdirTemp("", "agent-test-*")
+	if err != nil {
+		t.Fatalf("Failed to create temp dir: %v", err)
+	}
+	defer os.RemoveAll(tmpDir)
+
+	cfg := &config.Config{
+		Agents: config.AgentsConfig{
+			Defaults: config.AgentDefaults{
+				Workspace:         tmpDir,
+				Model:             "test-model",
+				MaxTokens:         4096,
+				MaxToolIterations: 10,
+			},
+			List: []config.AgentConfig{
+				{ID: "worker"},
+			},
+		},
+		Tools: config.ToolsConfig{
+			Message: config.ToolConfig{Enabled: true},
+		},
+	}
+
+	msgBus := bus.NewMessageBus()
+	al := NewAgentLoop(cfg, msgBus, &mockProvider{})
+
+	worker, ok := al.registry.GetAgent("worker")
+	if !ok {
+		t.Fatal("expected named agent to be registered")
+	}
+
+	tool, ok := worker.Tools.Get("message")
+	if !ok {
+		t.Fatal("expected message tool to be registered on named agent")
+	}
+
+	messageTool, ok := tool.(*tools.MessageTool)
+	if !ok {
+		t.Fatalf("expected *tools.MessageTool, got %T", tool)
+	}
+
+	messageTool.ResetSentInRound()
+	result := messageTool.Execute(
+		tools.WithToolContext(context.Background(), "discord", "chat-1"),
+		map[string]any{"content": "tool message"},
+	)
+	if result == nil || result.Err != nil {
+		t.Fatalf("message tool execute failed: %+v", result)
+	}
+
+	sessionKey := routing.BuildAgentMainSessionKey(worker.ID)
+	al.publishResponseIfNeeded(context.Background(), sessionKey, "discord", "chat-1", "final response")
+
+	select {
+	case msg := <-msgBus.OutboundChan():
+		if msg.Content != "tool message" {
+			t.Fatalf("first outbound content = %q, want %q", msg.Content, "tool message")
+		}
+	default:
+		t.Fatal("expected tool message to be published")
+	}
+
+	select {
+	case msg := <-msgBus.OutboundChan():
+		t.Fatalf("unexpected duplicate outbound message: %+v", msg)
+	default:
+	}
+}
+
 func TestProcessMessage_UseCommandLoadsRequestedSkill(t *testing.T) {
 	tmpDir := t.TempDir()
 	skillDir := filepath.Join(tmpDir, "skills", "shell")